projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| d149e2aa KM |
1 | .\" Copyright (c) 1980 Regents of the University of California. |
| 2 | .\" All rights reserved. The Berkeley software License Agreement | |
| 3 | .\" specifies the terms and conditions for redistribution. | |
| 4 | .\" | |
| 5 | .\" @(#)chmod.2 4.1 (Berkeley) %G% | |
| 6 | .\" | |
| 7 | .TH CHMOD 2 | |
| 8 | .UC 4 | |
| 9 | .SH NAME | |
| 10 | chmod \- change mode of file | |
| 11 | .SH SYNOPSIS | |
| 12 | .nf | |
| 13 | .B chmod(name, mode) | |
| 14 | .B char *name; | |
| 15 | .fi | |
| 16 | .SH DESCRIPTION | |
| 17 | The file whose name | |
| 18 | is given as the null-terminated string pointed to by | |
| 19 | .I name | |
| 20 | has its mode changed to | |
| 21 | .IR mode . | |
| 22 | Modes are constructed by | |
| 23 | .IR or ing | |
| 24 | together some | |
| 25 | combination of the following: | |
| 26 | .PP | |
| 27 | .RS | |
| 28 | 04000 set user ID on execution | |
| 29 | 02000 set group ID on execution | |
| 30 | 01000 save text image after execution | |
| 31 | 00400 read by owner | |
| 32 | 00200 write by owner | |
| 33 | 00100 execute (search on directory) by owner | |
| 34 | 00070 read, write, execute (search) by group | |
| 35 | 00007 read, write, execute (search) by others | |
| 36 | .RE | |
| 37 | .PP | |
| 38 | If an executable file is set up for sharing (this is the default) | |
| 39 | then mode 1000 prevents the system from | |
| 40 | abandoning the swap-space image of the program-text portion | |
| 41 | of the file when its last user | |
| 42 | terminates. | |
| 43 | Ability to set this bit is restricted to the super-user | |
| 44 | since swap space is consumed | |
| 45 | by the images. | |
| 46 | See | |
| 47 | .IR sticky (8). | |
| 48 | .PP | |
| 49 | Only the owner of a file (or the super-user) may change the mode. | |
| 50 | Only the super-user can set the 1000 mode. | |
| 51 | .PP | |
| 52 | On some systems, | |
| 53 | writing or changing the owner of a file | |
| 54 | turns off the set-user-id bit. | |
| 55 | This makes the system somewhat more secure | |
| 56 | by protecting set-user-id files | |
| 57 | from remaining set-user-id if they are modified, | |
| 58 | at the expense of a degree of compatibility. | |
| 59 | .SH "SEE ALSO" | |
| 60 | chmod(1) | |
| 61 | .SH DIAGNOSTIC | |
| 62 | Zero is returned if the mode is changed; | |
| 63 | \-1 is returned if | |
| 64 | .I name | |
| 65 | cannot be found or if the current user | |
| 66 | is neither the owner of the file nor the super-user. | |
| 67 | .SH "ASSEMBLER (PDP-11)" | |
| 68 | (chmod = 15.) | |
| 69 | .br | |
| 70 | .B sys chmod; name; mode |